Halfrith

Distance lenses that correct blurry vision for far away objects, while things up close remain clear.

Multifocal lenses that improve your vision for objects both near and far away.

Reader and intermediate lenses for those who have trouble focusing while reading.

Lenses that complement your personal style.

It’s just what it sounds like — the distance in millimeters (mm) between your pupils. An average PD measurement in 63mm, but it varies by person. If your PD number isn’t on your prescription, you can measure it yourself by:

Lens strength needed to correct your vision. Positive (+) means farsighted, negative (-) means nearsighted.

The degree of astigmatism in your eyes, as well as an axis number that indicates the orientation of the astigmatism.

ADD stands for the additional correction that you need for reading. It’s used for multifocal lenses and readers.

Prism is power, measured in diopters, used to correct vision displacement, like double vision or an eye turn. Most eyeglass prescriptions do not have prism correction. A prescription with prism will have two values per eye: a Prism (power) and Base (direction).

Vertical prism correction is for vertical eye misalignments & prescribed upwards in one eye and downwards in the other.

Horizontal prism correction is for lateral eye misalignments & prescribed in the same direction for both eyes.

The Flat-Top bifocal is the most common and popular design. It features a distinct D-shaped segment for near vision, neatly embedded in the lower part of the distance lens. The flat top on this segment creates a clear horizontal line, making it easy to distinguish between the two vision zones. It offers an excellent balance of a wide reading area, comfortable adaptation, and a relatively discreet appearance compared to other lined bifocals.

Ideal for: First-time bifocal wearers and those seeking a reliable, all-purpose solution for clear distance and near vision.

Our 1.55 index bifocal with line lenses are typically made as flat-top bifocals by default.

The E-Line, or Executive bifocal, is recognized by its prominent horizontal line that runs across the entire width of the lens. The entire area below this line is dedicated to near vision, providing the largest possible reading area of any bifocal type. This full-width design completely eliminates "image jump," offering a seamless transition for tasks like reading across a wide page. The trade-off is a more visible line and lenses that are typically thicker and heavier.

Ideal for: Users who require a vast, unrestricted field of view for extensive near-vision work and prefer stability over cosmetics.

Our 1.61 index bifocal with line lenses are typically made as flat-top bifocals by default.